Provides access to Ethernet high-performance LAN adapters by way of the Ethernet device handler.
The /dev/entn character special file provides access to the Ethernet device handler for the purpose of providing access to an Ethernet LAN. The device handler supports up to four adapters, each of which may be running either or both of the standard Ethernet and IEEE 802.3 protocols.
When accessing the Ethernet device handler, the following should be taken into account:
The device handler can be loaded and unloaded. The handler supports the configuration calls to initialize and terminate itself.
Calls other than the open and close subroutines are discussed based on the mode in which the device handler is operating.
The Ethernet device handler supports the open and close, read, write, and ioctl subroutines in the following manner:
The device handler supports the /dev/entn special file as a character-multiplex special file. The special file must be opened for both reading and writing (O_RDWR). However, there are no particular considerations for closing the special file. The special file name used in an open call depends upon how the device is to be opened. Types of special file names are:
| /dev/entn | An open call to this device is used to start the device handler for the selected port, where the value of n is 0 <= n <= 7. |
| /dev/entn/D | An open call to this device is used to start the device handler for the selected port in diagnostic mode, where the value of n is 0 <= n <= 7. |
Can take the form of a read, readx, readv, or readvx subroutine. For this call, the device handler copies the data into the buffer specified by the caller.
Can take the form of a write, writex, writev, or writevx subroutine. For this call, the device handler copies the user data into a buffer and transmits the data on the LAN.
The Ethernet device handler supports the following ioctl operations:
| CCC_GET_VPD | Returns adapter vital product data (VPD) if available and valid. |
| CIO_GET_FASTWRT | Returns the parameters required to issue an ent_fastwrt call. |
| CIO_GET_STAT | Returns current adapter and device handler status. |
| CIO_HALT | Halts a session and unregisters a network ID. |
| CIO_QUERY | Returns the current RAS counter values, as defined in the sys/comio.h and sys/entuser.h files. |
| CIO_START | Starts a session and registers a network ID. |
| ENT_SET_MULTI | Sets or clears a multicast address. |
| IOCINFO | Returns a device information structure to the user specified area. The devtype field value is DD_NET_DH and the devsubtype field is value DD_EN, as defined in the sys/devinfo.h file. |
The following error codes may be returned when accessing the device handler through the dev/entn special file:
| EACCES | Permission to access the port is denied for one of the following
reasons:
|
| EAFNOSUPPORT | The address family is not supported by the protocol, or the multicast bit in the address is not set. |
| EAGAIN | The transmit queue is full. |
| EBUSY | The request is denied because the device is already opened in Diagnostic mode, or the maximum number of opens was reached. |
| EEXIST | The define device structure (DDS) already exists. |
| EFAULT | An address or parameter was specified that is not valid. |
| EINTR | A subroutine call was interrupted. |
| EINVAL | A range or operation code that is not valid was specified, or the device is not in Diagnostic mode. |
| EIO | An I/O error occurred. |
| ENOBUFS | No buffers are available. |
| ENOCONNECT | A connection was not established. |
| ENODEV | The device does not exist. |
| ENOENT | There is no DDS to delete. |
| ENOMEM | The device does not have enough memory. |
| ENOMSG | No message of desired type was available. |
| ENOSPC | No space is left on the device (the multicast table is full). |
| ENOTREADY | The device is not ready, a CIO_START operation was not issued, or the operation was issued but did not complete. |
| ENXIO | The device does not exist, or the maximum number of adapters was exceeded. |
| EUNATCH | The protocol driver is not attached. |
The close subroutine, open subroutine, read or readx subroutine, write or writex subroutine, ioctl subroutine.